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Somewhat O/T I, Slide Rule
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Author:  superheater [ Sat May 08, 2010 12:43 am ]
Post subject:  Somewhat O/T I, Slide Rule
This is a bit off topic, but I suspect there might be a some interest in "paleotech" .

Normally a journal of hardcore libertarian opinion, there's an interesting article in the Freeman online about the emergence of slide rules as "objects of art". Adaptive reuse on a microscale?

One of my early 80's college professors encouraged his students to acquire, learn and love a good slide rule, with the primary advantage being no dead batteries. He failed miserably, with TRON in the movies and TI SR-50/51's in the college bookstore promising novelty.

Much like the first generation diesels that replaced steam, a working HP or TI "Slide Rule" calculator that replaced the "log-log-decitrig", is itself a relic and like some early diesels, parts for the bright red LED calculators are matter of scavenging an ever diminishing supply. Ironically, the calculator model from the 80's that is still produced is the HP-12c, a "business model", that calculates present values but no cosines. It's ironic because Lotus 1-2-3/MS Excel, especially on laptops was supposed to be the tool of choice for the bean counter crowd.

I picked up a K&E 40something, complete with manual and original case a few years ago, intending to learn to use it as something of challenge,but oh well.

Of course, as archaic as a slide rule now seems, it made the engineering work of the 19th and especially the 20th century possible and for the original geeks, it could be played like a fine instrument.
[url]
http://www.thefreemanonline.org/featured/i-slide-rule/[/url]
Author:  Bruce E. Babcock [ Sat May 08, 2010 9:02 pm ]
Post subject:  Re: Somewhat O/T I, Slide Rule
This might not be as far "off topic" as it first appears.

Early in his career, James Watt apprenticed as a rule maker. Years later, he combined his knowledge of rule making with his knowledge of engineering and devloped what is considered to be the first slide rule for mechanical engineers. I believe that the Science Museum in London has at least one of his slide rules. The slide rule was invented in 1630, and until Watt's improvements, they were used primarily to perform timber calculations and by tax collectors to determine the volumes of irregularly shaped containers of spirits.

Not too far afield from this is the fact that it was one of Watt's engineers, John Southern, who, in 1796, developed the first device that was capable of automaticlly generating a graph. This device was know as the steam engine indicator and was used extensively on locomotives and on all other types of steam engines.

The invention of the steam engine indicator led to developments in other mathematical instruments; the polar and linear planimeters.

Bruce E. Babcock
Author:  isaksenj [ Sun May 09, 2010 1:59 pm ]
Post subject:  Re: Somewhat O/T I, Slide Rule
As someone who went through his first several years of Structural Design at the very dawn of the Pocket Calculator age, I was probably among the last classes subjected to that Infernal creation, "to three significant figures".

(If you ever see photos of geeky-looking Engineering students walking around with a something that looks like a cross between a holster and a short sword scabbard hanging from their belts, you now know what those held!)

For those of you with a burning desire to play with a slide rule, you can download an app:

http://itunes.apple.com/us/app/slide-ru ... 54455?mt=8
Author:  robertmacdowell [ Sun May 09, 2010 8:32 pm ]
Post subject:  Re: Somewhat O/T I, Slide Rule
I have my old TI-30 calculator. I also have my old slide rule. Guess which one still works.

You know that disc on the front of any Doall band saw, that you rotate and it tells you stuff about materials, blade speeds and the like?
http://www.interplantsales.com/images/260/100.jpg

That thing still works on an old Doall, or it has fallen out and the machine still works and you just need a copy of a machinery handbook at hand to get those settings right. On the new machines, the disc goes away and it's replaced by a computer controlled readout which actually controls the machine. At some point, the electronic control gets a funny smell to it, and it's found to be unrepairable and no longer supported by the manufacturer. Without it, the whole machine is junk.

As museums, we get old machine tools because we can't afford new ones. Our window of opportunity is slowly closing on those old manual machines that will run forever.
Author:  artschwartz [ Mon May 10, 2010 12:02 am ]
Post subject:  Re: Somewhat O/T I, Slide Rule
Robert:
You have also made a good case for the impracticality of keeping modern rail equipment in operable condition in the museum environmet. For example, your Boeing LRV.
Author:  JimBoylan [ Mon May 10, 2010 9:29 am ]
Post subject:  Re: back to topic, modern equipment.
When Penn's Landing's trolley, Red Arrow ex-Hog Island car 26 with Pneumatic Cam automatic acceleration MU controls, was vandalized, the Museum worried that the only way it would run again was to do like Philadelphia Transportation Co. did with similar cars, convert to manual K controls. Replacement parts are no longer stocked by the manufacturer. When Baltimore Sreetcar Museum had a problem with somewhat similar controls breaking into small fragments on their car 6119, they just had their shop blacksmith and machinist make the replacement parts! In the future, your museum's salvation may be the resident geek who thinks that integrated circuits are the easiest and most interesting things in the world since steam engines were invented.
Author:  survivingworldsteam [ Mon May 10, 2010 12:17 pm ]
Post subject:  Re: Somewhat O/T I, Slide Rule
My high school Physics teacher also required us to learn to use a slide rule in his class my Senior year. When I started college, the Engineering department then required us to purchase a TI-58C; which sold for the princely sum of $100 in the early 1980s.

I sometimes wonder how much CAD/CAM and computers have really helped innovation; and may have stifled it instead. Both the Concord and the SR-71 were built using slide rules; I think the Apollo rocket was as well. With all the computational power we have amassed; we seem to have very little gain to show for it.
Author:  Mike Swanson [ Wed May 12, 2010 1:04 pm ]
Post subject:  Re: Somewhat O/T I, Slide Rule
artschwartz wrote:
Robert:
You have also made a good case for the impracticality of keeping modern rail equipment in operable condition in the museum environmet. For example, your Boeing LRV.

...Which isn't really saying much, since Muni and MBTA could barely keep the Boeing LRVs operable either! Yet one more reason why aerospace companies should stay out of the rail/transit equipment business...
Author:  David H. Hamley [ Wed May 12, 2010 1:28 pm ]
Post subject:  Re: Somewhat O/T I, Slide Rule
No real engineer who started life with a slide rule has ever been able to throw one away. I still have my 1961 vintage K&E Log/Log Duplex Decitrig and case. The rule is made of bamboo veneered with plastic. Still works just fine.

I later graduated to an SR50 (for $175, so you know it was a while ago) with it's lovely glowing digits. That still works too, after several transplants of its original battery pack with modern cells.

The current favorite device is the TI30SLR, bought on closeout for $8.88 when panic dictated that I had just several hours to submit 4 weeks of expense reports--or lose the payment!

Art Schwartz and I (we both belong to Pennsylvania Trolley Museum) have discussed the impending trials of preserving and trying to operate in a museum environment one of the latter day (1970s on) LRVs. There are several roadblocks. Such cars are loaded with printed circuit boards that are populated with mostly obsolete descrete components. Each board requires a test fixture for proper maintenance. Microprocessor chips will be especially difficult to "reverse engineer" after one dies. How about programming languages that haven't been used commercially for decades? Then there's air conditioning systems that were designed for the now banned R12 Freon. Chopper controls for the motors depend on beefy semiconductor devices, huge capacitors (PCBs?), and of course, more printed circuit boards, which are another definition of PCB.

It will indeed be a challenge to the "hammer, WD40 & duct tape" kind of personnel to keep such an LRV running for more than a couple trips. Perhaps it would be best to consider them as static displays and continue to pile up the mileage on 1920s conventional cars and PCCs.
Author:  Mike Swanson [ Wed May 12, 2010 1:37 pm ]
Post subject:  Re: Somewhat O/T I, Slide Rule
survivingworldsteam wrote:
My high school Physics teacher also required us to learn to use a slide rule in his class my Senior year. When I started college, the Engineering department then required us to purchase a TI-58C; which sold for the princely sum of $100 in the early 1980s.

I sometimes wonder how much CAD/CAM and computers have really helped innovation; and may have stifled it instead. Both the Concord and the SR-71 were built using slide rules; I think the Apollo rocket was as well. With all the computational power we have amassed; we seem to have very little gain to show for it.

That's probably true. Too many people now either depend too much on modern technology and not their own imagination and creativity, or that same technology allows less creative souls to fool others into thinking that they are being innovative; good luck trying to do that with a slide rule and a drafting table! Modern CAD/CAM technology has made the design and engineering process easier (and has also made posssible some concepts and products - like stealth technology and modern microelectronics - which would have otherwise been impossible to develop and produce), but it's no substitute for the human mind and the organic computer known as the human brain.
Author:  Al Patterson [ Wed May 12, 2010 7:16 pm ]
Post subject:  I still have the plastic one I purchsed for Chemistry class
in 1972 or 1973. Unfortunately, it is a cheap(ish) plastic model.

I use it from time to time to do simple stuff, just to see the looks I get when people see me use it.
Author:  o anderson [ Wed May 12, 2010 8:40 pm ]
Post subject:  Re: Somewhat O/T I, Slide Rule
Quote:
Perhaps it would be best to consider them as static displays and continue to pile up the mileage on 1920s conventional cars and PCCs.


This has always been my perspective on streetcar technology. I have ridden PCCs and modern stuff and am finding myself more impressed by the simple and stable nature of a PCC every time. In addition, noise levels on modern equipment is sometimes baffling. I wonder why "new" 1980s LRVs in Philly whine and screetch, when the older cars just hum a little. I would be glad to let a newer (unsupportable silicon) car or diesel moulder at a museum, and at the same time enjoy the simple pleasures of pre- 1960 control systems on the operating equipment.

That is not to say that anything 1960 to present is not supportable, just that it seems increasingly less so as our technology becomes more disposable.
O.
Author:  Fitz [ Wed May 12, 2010 10:50 pm ]
Post subject:  Re: Somewhat O/T I, Slide Rule
Image
My Post Versalog log-log-duplex trig. It didn't help design the SR-71, but it helped calculate some data during the SR-71 flight tests.
Author:  Bruce E. Babcock [ Thu May 13, 2010 5:40 pm ]
Post subject:  Re: Somewhat O/T I, Slide Rule
Mike Said "Too many people now either depend too much on modern technology and not their own imagination and creativity, or that same technology allows less creative souls to fool others into thinking that they are being innovative;..."

These are basically the same concerns that Willilam Oughtred had in 1630 when he concealed the invention of his slide rule for several years. He said that he did not want his math students to be simply "... doers of tricks."

Bruce E. Babcock
Author:  robertmacdowell [ Fri May 14, 2010 4:36 am ]
Post subject:  Re: Somewhat O/T I, Slide Rule
David H. Hamley wrote:
Art Schwartz and I (we both belong to Pennsylvania Trolley Museum) have discussed the impending trials of preserving and trying to operate in a museum environment one of the latter day (1970s on) LRVs. There are several roadblocks. Such cars are loaded with printed circuit boards that are populated with mostly obsolete descrete components. Each board requires a test fixture for proper maintenance. Microprocessor chips will be especially difficult to "reverse engineer" after one dies. How about programming languages that haven't been used commercially for decades?


Well, we have one big thing in our favor: the companies for whom the cars are built, still exist. And we have a fair chance of getting design specifications and technical docs.

I once met Steve Wozniak. I asked him if it was still possible to make the Apple I. He said "Hmm, probably not, I think the shift registers went out of production." But on the other hand, we can emulate an Apple I in SOFTWARE. On anything from a "One Laptop Per Child" netbook, to an iPhone, to an Arduino.

Quote:
Chopper controls for the motors depend on beefy semiconductor devices, huge capacitors (PCBs?), and of course, more printed circuit boards, which are another definition of PCB.

No problem there, the cost of those beefy semiconductors has been dropping like a stone - kinda like electronics costs tend to do generally. Replicating the functionality of a 25-year-old chopper seems well within the reach of, say, the folks who make the Zilla controller for EV's.

Quote:
Perhaps it would be best to consider them as static displays and continue to pile up the mileage on 1920s conventional cars and PCCs.

Depends. The old things wear out too, and I think when a heavy maintenance event occurs, the car is simply sidelined and replaced with another. Do you know any railway museums who have dealt with scary problems, like catastrophic armature bearing failures, or even just needing to rewind a motor? We certainly know how tough it is to replace a crown sheet on a super-power steamer.
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